Timing speeds of varying lengths of straight cylinder vents

[Larry Pletcher]

Discussions of posts about exterior cons, vent lengths, including PMs have me considering a test that would time varying lengths of straight cylinder shaped vents.  Right now I'm thinking of a barrel stub with a solid vent liner - no cones inside or out.  Its length would be the width of the barrel wall.  I would begin by timing a 1/16" hole in the vent. After the timing session, remove the vent and take .010" off the inside.  I'd then reinstall and retime.  I would remove, take off another .010" and retest.  A series of tests like this should address the issue of whether the length of a straight vent affects the ignition speeds. 

My gut says that a short vent would be quicker than a long vent.  But, I know of no test of ignitions speeds like this has been done.  Any suggestions?

Regards,
Pletch

[bob in the woods]

Very interesting. I look forward to the results. Except for my target rifle, my fowlers and rifles are all used for hunting.
From experience , I found that reliability and performance went to near 100% when I standardized on a 5/64th's vent
Rain, snow, heat, and cold, ...everything the outdoors can throw at you .   

[Brokennock]

Should be interesting. Are you going to make the vent liner yourself by drilling out a set screw? If so, I'm wondering if it can be made so it can be threaded in from either end, thus being able to test if there is a difference between the wall being thinner by removal of material from the inside or from the outside of the liner/barrel wall. I hope I explained that okay.

[Joe S]

e-mail sent.

[LH]

stands to reason that the shorter the faster,   but how much?     I'd love to see this test

[Larry Pletcher]

With help from a couple friends, I'm working out methodology for this test. Right now I can say that it will include multiple lengths of vents and enough trials with each to make proper statistical sense.  In that area I will have expert help. I'll describe this process we have more of this firmed up.

Regards,
Pletch